Vaisala HMP3 - Modbus Communication Reference; Default Modbus Settings; Modbus Function Codes

Appendix A. Modbus reference
A.1 Default communication settings
Table 52 Default Modbus serial communication settings
Property Description/value
Serial bit rate 19200
Parity None
Number of data bits 8
Number of stop bits 2
Flow control None
Modbus device address 240
You can use up to ten probes on the same RS-485 line. You must configure each probe on the
line to have a dierent Modbus address.
A.2
Function codes
Table 53 Modbus function codes
Function code
(decimal)
Function code
(hexadecimal)
Name Notes
03 03
hex
Read Holding
Registers
Class 0
16 10
hex
Write Multiple
Registers
Class 0
43 / 14 2B
hex
/ 0E
hex
Read Device
Identification
A.3 Data encoding
In the data registers, the numeric values are available in one or two formats with separate
register addresses: 32-bit IEEE floating point format and/or 16-bit signed integer format.
Appendix A – Modbus reference
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